The original five-year INIA West has identified a large number of candidate genes that are differentially expressed in the brains of mice selectively bred for either high- or low-preference for alcohol. Additional conserved genes were identified in screens for alcohol tolerance in Drosophila. Manipulating the expression of these genes has naturally become a critical component of studies designed to further define their role in the development of alcohol preference or tolerance. The RNA Interference Core (RNAi Core) will provide a means for systematic modification of the target genes'expression in selected and precisely-defined brain areas. Two technological platforms for in vivo RNA interference will be employed: (1) small interfering RNA (siRNA) delivered by a direct injection or infusion into the CNS and (2) short hairpin RNA (shRNA) delivered via a lentiviral vector-based transduction. Initially, these methods will be standardized using transcripts identified in HAP and LAP mice as contributing to alcohol preference drinking behavior, and the functional consequences of the RNAi treatment will be assessed in these mice. The successful implementation of the methodology will provide an important resource for all INIA investigators, including those working with rat models. At the time of this submission, laboratories from California, Colorado, Indiana, Oregon and Texas are already collaborating in both Binge and Dependence Domains. The core will also perform RNAi treatments for INIA investigators, who will develop need for RNAi services with the emergence of additional target genes. Proposed projects will be evaluated for integration with INIA West goals by a Project Evaluation Committee composed of members of the INIA Steering Committee and an independent consultant. The core will capitalize on our ongoing collaboration with Dharmacon Corporation, a leader in the field of siRNA development. Dharmacon will provide many of the necessary reagents and work with us on improving the efficiency of gene silencing in the CNS. The core's goals will be accomplished by successful completion of the following aims: Aim 1. Perform high throughput in vitro screening of the RNAi sequences targeting the genes of interest. Aim 2. Silence expression of selected genes in vivo employing RNAi within precise neuroanatomical targets. Aim 3. Examine behavioral and transcriptional effects of gene silencing. The creation of the RNAi core is a logical extension of the work already completed by the INIA. The core will allow for systematic and high throughput manipulation of genes in the mammalian CNS, facilitating functional studies of these genes in alcohol preference.